Railway signal system.



No. 725,674. PATENTED APR. 21, 1903;

I J. P. COLEMAN. RAILWAY SIGNAL SYSTEM.

APPLIOATION FILED JAN. 30, 1903.

N0 MODEL.

WITNESS m INVENTUR THE mums FETER$ no. PHOTO LlTNO.. WASHINGTON, c. c.

Nrrnn STATES PATENT @FFICE.

JOHN PRESSLEY COLEMAN, OF EDGE'WOOD PARK, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH AND SIGNAL COMPANY, OF SWISSVALE, PENN- SYLVANIA, A CORPORATION OF PENNSYLVANIA.

RAILWAY SIGNAL SYSTEM.

SPECIFICATION forming part of Letters Patent No. 725,674, dated April 21, 1903. Application filed January 30, 1903. Serial No. 141,091. (No model.)

To all whom it may concern: efforts to maintain aworking pressure Within Be it known that I, JOHN PREsSLEY OOLE- the pipe-line. Such occurrences result in the MAN, a citizen of the United States, residing derangement of the signal system and cause at Edgewood Park, in the county of Allemany signals to move to display dangerindigheny and-State of Pennsylvania, have'incation to trains improperly, causing in convented certain new and useful Improvements sequence delays and confusion of traffic upon in Railway Signal Systems, of which the folthe railway. In order that such occurrences lowing is a specification. may be nullified or largely nullified in so far My invention relates to improvements in as they effect the operation of the signals, I to that character of signal system wherein fluid have devised a new and novel arrangement under pressure is required to be maintained of the conductors by which the signals are constantly at fixed points along a line of railsupplied with fluid-pressure. This arrange. way-track, to the end that prompt and uninment comprises reservoirs, one located at terrupted service may be obtained from the each signal and having a check-valve in the :5 system so operated or controlled. The finid-' connection between the reservoir and the pressure employed usually consists of atmosmain conductor or pipe, so arranged as to be pheric air raised to the desired pressure for unseated by flow of fluid from the main conoperating the signal devices and is developed ductor into the reservoir and to be seated at and maintained at one or more points along other times, so as to absolutely prevent all 20 the system by suitable compressing-engines. flow of fluid from the reservoir into the main It has been the general custom in arrangpipe should the pressure within the main pipe in g such systems to provide a continuous confall below that in the reservoir for any reason ductor for the fluid-pressure from each point whatsoever-such, for instance, as from a at which the pressure is used to the next adbreak in the main pipe or a stoppage of the 25 jacent point, thus, in effect, producing a concompressing-engines. The fluid in the main 7 5 tinuous conductor or pipe throughout the syspipe and reservoir is preferably maintained tern of signals, with branches therefrom to at a much higher pressure than the minimum each signal embodying the fluid-pressure. required by the signal device for its opera- Where long pipe-lines are employed, as on extion and in a volume greatly in excess of that 30 tensive systems covering many miles of railwithdrawn from the reservoir by each operaway, these compressors are required to detion of the signal in order that the contents velop a higher pressure than that required of the reservoir during emergencies may rep for the operation of each individual signal resent sufficient energy of itself to operate device in order that a certain reserve energy the signal until the emergency has passed and 5 may be present that may be called upon to the normal delivery of fluid at the normal meet the emergency of a fractured pipe-line pressure in the system is again established. or a temporary stoppage of the compressors In my invention also it is not of great imfor repairs, 850., without necessarily interportance that compressors be located at each rupting the operation of the signal system. extremity of the pipe-line, as itheretofore has .40 This excess energy is also useful in accelerbeen found advisable to arrange them. One 0 ating the flow of the fluid-pressure through compressor centrally located may maintain the pipe-line to those signals most remote more free from interruptions the service of a from the compressors and is a most important given signal system than would under like factor in the maintenance'of a comparatively conditions the use of two compressors, one 5 uniformpressure throughoutalongpipe line. at each end of the same system,under the 5 A fracture of the pipe-line or any of the methods heretofore followed. branch pipes of such a system may be and a I will describe a railway signal system emnumber of times has been of such a characbodying my invention and then point out the ter as to efiectually overtax the capacity of novel features thereof in a claim. 50 all of the compressors of the system in their In the accompanying drawings, Figure l is too a diagrammatic view of a portion of a doubletrack railway, the railway-signals provided for each track, the pipe-line for the fluidpressnre, and the connections to the signals for one line of track. Fig. 2 is a View of a portion of the apparatus'drawn to a larger scale.

Similar letters of reference designate corresponding parts in both of the figures.

A and B designate the two lines of railwaytrack, A the signals governing the passage of trains on one track, and B the signals governing the passage of the trains on the other track. O designates an air-compressor, which may be located at a suitable point along the line of railway, and D a main pipe-line leading therefrom and extending along the line of railway-track. At each signal-point a branch dis tapped into the main pipe-line, and each branch is provided with a stop-cock d.,-a.checkvalve-d which is unseated by the flow of compressed air from the main pipe-line, and a reservoir d The check-valve cl may be of any desired construction, provided it acts to prevent any flow of compressed air from the reservoir d when. the pressure in the main pipe-line D is lowered below that in the reservoir. A pipe 0 leads from each reser- Voir and has one or more branches d leading therefrom, according to the number of fluidpressure mechanisms to be operated. In the drawings I have shown two branches, one for the home signal and one for the distant signal, both of which are here shown as being mounted on the same post or support. Any of the well-known types of fluid-pressure mechanism may be employed, and the elecfor the signals of which are operated by fluid-' pressure, the combination of a fluid-pressure generator, a pipe-line leading therefrom, a'

reservoir connected therewith and from which the supply of fluid-pressure for operating the signals is obtained, a check-valve in the connection between the pipe-line and the reser- .Voir and a controlling device in the connection between the reservoir and signal-operating mechanism.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

JOHN PRESSLEY COLEMAN.

Witnesses: I

GEO. E. (Ross, W. L. MODANIEL. 

